To the Editor.
—We were interested in the study by Jaffe and associates,1 disclosing the potential use of immunotoxins to inhibit the growth of retinal pigment epithelial cells in patients with proliferative vitreoretinopathy (PVR). Exposing the proliferating retinal pigment epithelial cells to an immunotoxin composed of a monoclonal antibody directed against transferrin receptor and conjugated to ricin A chain, caused a significant decrease in the number of cells and affected their morphologic appearance. This study was based on the hypothesis that transferrin receptors, which are expressed at high density on various types of proliferating cells, could constitute a useful target for immunotoxins, whereby proliferating retinal pigment epithelial cells would be inhibited during PVR.This hypothesis, however, was investigated by studying the cells in vitro, not in vivo, so that it could be determined whether such antiproliferative agents might be used in patients with PVR. We have been studying PVR
Baudouin C, Brignole F, Gastaud P. Transferrin Receptor Expression by Retinal Pigment Epithelial Cells in Proliferative Vitreoretinopathy. Arch Ophthalmol. 1991;109(9):1195-1196. doi:10.1001/archopht.1991.01080090017007